1. Field of the Invention
The invention relates to an auxiliary device for displacing a payload receptacle of an elevator and to a device for monitoring the position and the movement of a cage in a shaft of an elevator.
2. Description of the Related Art
Elevators with an auxiliary device of that kind are usually used for the transport of persons or goods in a vertical direction between at least two vertically offset stations and are arranged in an elevator shaft in or at a building. The wall bounding the elevator shaft has at the level of each station a loading/unloading opening which is closable by means of a door device and at which a waiting zone adjoins, in which the payloads are disposed before loading or after unloading of the payload receptacle. Such an elevator essentially comprises a payload receptacle such as a platform or a cage, a counterweight for the payload receptacle, a drive device, a braking device, at least one flexible support and drive element, such as for example a cable or rope, and the necessary electronic power and control system. The flexible support and drive element connects the payload receptacle with its counterweight and runs between the payload receptacle and counterweight by way of a drive wheel of the drive device. The drive device is disposed in the transport shaft above the zone thereof usable by the payload receptacle. If braking takes place in consequence of a technical problem, thus an emergency braking, the load receptacle is usually not disposed in a station. The auxiliary device then has to be actuated in order to bring the load receptacle to a station in the shortest time, so that the persons and/or goods being transported do not have to remain in or on the load receptacle in the transport shaft. The auxiliary device comprises on the one hand a temporarily activatable brake release device, by which the braking device is released, and on the other hand an auxiliary drive device actuable in the case of emergency in order to raise or lower the load receptacle when the release device is activated; in that case, the load receptacle has to be brought into one of the stations or at least in to a region in the vicinity of a station where a risk-free unloading can take place. The auxiliary drive device is generally constructed so that it allows manual actuation of the drive pulley, which in normal operation is actuated by motor, of the drive device; consequently, this drive pulley can also be considered as part of the auxiliary drive device. For elevators which are mounted in buildings with few storeys and are designed for transport of relatively small payloads, simple, manually actuable and mechanically operating brake release and auxiliary drive devices are preferably provided.
EP 0 947 460 A1 describes such an auxiliary device for an elevator for persons, with a release device and an auxiliary drive device. This possesses a crank rod linkage, which is so constructed that it is used not only for activating a brake release device, but also for the drive of an auxiliary drive device. The upper end region of the crank rod linkage can be coupled with the brake release element and with the element of the auxiliary drive and is disposed in the uppermost part of the transport shaft. The crank rod linkage is constructed to be pivotable and mounted in such a manner that it can be pivoted from a rest position in which it is disposed entirely in the elevator shaft into an operative position in which its lower end region projects through a window opening of a wall bounding the elevator shaft. The window opening lies in the upper region of the uppermost station, so that the crank rod linkage can be readily actuated at its lower end by way of appropriate handle elements by a person standing in the waiting zone of the station. The disadvantage of this device is to be seen in that the actuation thereof has to take place at the level of the uppermost station; this disadvantage is of particular significance when this station is disposed within a residential unit, as is frequently the case in superior dwellings and particularly in maisonette dwellings and penthouse dwellings.
There is known from DE GM 296 15 921 U1 an auxiliary device which is improved with respect thereto and in which the operation of the device can take place from a location disposed at a certain distance from the uppermost station of the elevator. However, this auxiliary device is of comparatively complicated construction. A substantial disadvantage of such auxiliary devices resides in the fact that it is not possible for a person who is actuating it to observe the movement, which is taking place in the uppermost region of the elevator shaft, of the auxiliary drive device as generally no direct visual link exists between this uppermost region of the elevator shaft and the person carrying out the operation. Certainly with a suitable arrangement of an observation window the flexible support and drive element at which the load receptacle is suspended can be observed without further measures from a location outside the elevator shaft and thus an indication obtained about the movement of the payload receptacle, but in many cases this is considered to be an inadequate solution. In order to actually observe an element of the auxiliary drive device such as the drive pulley the person carrying out the operation is obliged to move at least his or her head and neck region into the elevator shaft, which forms a source of risk for this person and can hinder them during actuation of the auxiliary device.
Moreover, the view of the uppermost region of the elevator shaft through the payload receptacle is obstructed if this is disposed above the location of the person carrying out the operation.
It is therefore an object of the present invention to provide an auxiliary device for displacing a payload receptacle of an elevator and a device for monitoring the position and the movement of a cage in a shaft of an elevator which are simple with respect to construction, arrangement and operation and which can be operated from a storey lying at one or more levels below the uppermost storey.
The auxiliary device according to the invention comprises an image transmission device which essentially consists of a sensor, a display device and a transfer path. The sensor serves the purpose of detecting at least one image of the movement of the auxiliary drive. The display device serves the purpose of making visible the images, which are picked up by the sensor, for the attention of the person carrying out the operation. The transfer path serves for transmission to the display device of the images detected by the sensor. In the case of arrangement of the operating elements of the auxiliary device far below the uppermost floor, thanks to an image transmission device of that kind the display device can be mounted in the immediate vicinity of the operating elements of the brake release and auxiliary drive device.
In the case of the device according to the invention for monitoring the position and the movement of a cage in a shaft of an elevator there is provided a first means for monitoring the movement of the cage, which comprises a unit for detection of the movement, an information transmission path and a display unit. In addition, there is provided a second means for monitoring the position of the cage, which comprises a means for reproducing the position of the cage.
In a first embodiment of the auxiliary device the image transmission device thereof is formed by at least two mirrors. The first mirror serves as a sensor and is oriented towards the auxiliary drive; the second mirror serves as a display device and is oriented towards an observation window, which is arranged in the wall of the elevator shaft at the location provided for the person carrying out the operation. The transfer path is formed by the optical coupling region between the first and the second mirror. This arrangement is comparatively simple in construction and reliable in operation. Moreover, it allows visualization on the display device not only of an image of the movement of the auxiliary drive, but also of the constructional elements of the auxiliary drive itself and the surroundings thereof. However, attention must be given to mounting the mirror so that the payload receptacle does not reach into the transfer path and thereby interrupt it. Moreover, measures must be undertaken in order to sufficiently brighten the elevator shaft, including when the auxiliary device has to be set in motion due to a mains failure. The image transmission device can also comprise one or more additional mirrors arranged along the transfer path between the first and the second mirror. In that case, each mirror is oriented towards the two mirrors adjacent thereto in the transfer path. The additional mirrors in such an arrangement can be considered to be components of the transfer path. In order to obtain good image quality, it can be advantageous if individual mirrors have reflection surfaces which are not planar, but concave or convex.
Apart from the purely optical image transmission device with mirrors, there can also be provided an image transmission device in which the transfer path is formed by a continuous conductor connection. This gives rise to, inter alia, the following advantages; the transfer path can be extended as desired; there is no risk that the transfer path is interrupted by the payload receptacle; the display device can be mounted at a location which is optimum for the person carrying out the operation; and it is not necessary to provide an actual observation window in the wall of the elevator shaft, because a small passage in this wall suffices for passing through the conductor connection. By contrast to the image transmission device with mirrors, it is further not necessary to provide emergency lighting for the entire transfer path, as merely sufficient light has to be present to guarantee the function of the sensor.
In the case of an auxiliary device of which the image transmission device functions in optimum manner, the sensor is formed by a video camera and the display device by a monitor, wherein the conductor connection is formed by an electrical conductor connection connecting the video camera with the display device. As in the case of the image transfer device with mirrors, there appears on the display device, i.e. on the monitor, an image of the auxiliary drive device and also its immediate environment. It is thereby possible to obtain more accurate indications of malfunctions. Several video cameras can also be mounted at different places within the elevator shaft, wherein the images detected by them can be alternatively and selectably visualised on the monitor.
Auxiliary devices with an image transmission device of which the transfer path is formed by a conductor connection can also be conceived in such a manner that they comprise a rotary element which rotates fixedly with the shaft of the auxiliary drive device and the rotation of which is detected by the sensor. In that case there appears on the display device not an image of the auxiliary drive itself, but an image of the movement of the auxiliary drive.
A conventional tachometer device can be mounted, as the sensor, at the shaft of such a rotary element which is preferably identical with the shaft of the auxiliary drive. The conductor arrangement in this case is an electrical conductor arrangement. The display device, namely a conventional tacho display, can reproduce the image not only of a movement of the auxiliary drive device, but also of the speed thereof.
In another construction of the image transfer device with a conductor connection between the sensor and display device, the rotary element is constructed as a rotary disc and has light-permeable zones which are arranged at mutual angular spacings and generally at a constant radial spacing from the rotational axis of the rotary element. As a rotary element or rotary disc there is preferably used a drive pulley of the drive of the elevator, over which the flexible support and actuating elements for the payload receptacle run. Such a drive pulley constantly rotates during displacement of the payload receptacle. Arranged on one side of the rotary disc is a light source which is so oriented that the light beam emitted by it is incident on a sector of the radial region of the rotary disc in which the light-permeable zones of the rotary disc are disposed. The sensor is arranged on the opposite side of the rotary disc. The display device shows an image of the movement of the drive or of the auxiliary drive or of the rotary disc. The display device is, for example, a monitoring light which blinks at the rhythm in which the light-permeable zones rotate away below the beam emitted by the light source, so that a bright/dark alternation is visible. The spacing in terms of time of the bright/dark alternation is a measure of the speed of the auxiliary drive and thus also of the payload receptacle.
In an image transmission device of that kind the light source can be formed by a first element of a light barrier and the sensor by the complementary second element of the light barrier. The conductor connection is, in that case an electrical conductor connection.
In an image transmission device which is similar to that just described the sensor is formed by an input of an optical conductor arrangement. The optical conductor arrangement itself is the conductor connection or the transfer path. The output of the optical conductor connection is oriented towards the display device, which acts in the manner of a monitoring light. As in the case of the image transmission device with a tachometer or light barrier there is in this case transmitted not an image of the drive pulley itself, but merely an image of the movement of the drive pulley. However, it is possible with a modification of this arrangement to transmit an image of the drive pulley itself; for this purpose several optical conductors, for example n2 optical conductors must be used. The inputs and outputs of the conductors are respectively arranged in n columns to n lines. The larger the number n of optical conductors, the finer the scanning-pattern image that is received of the drive pulley.
The initially described construction of the image transmission device with mirrors has, as already mentioned, a non-material transfer path. This would be particularly advantageous in cases in which an existing elevator has to be subsequently equipped with an image transmission device. However, this is usually not possible with mirrors which need for that purpose a free space for the beam path near the load receptacle. Thereagainst, a comparatively simple and space-saving image transmission device can be realized if a non-material transfer path in the form of a radio or laser connection is used.
The new auxiliary device comprises, in accordance with the invention, an image transmission device which, as explained, can be constructed in very diverse ways. It is also possible to provide image transmission devices which consist of several serially arranged part devices constructed and operable in accordance with several of the above-described principles.
Advantageously, in the case of the device according to another embodiment of the invention, a drive unit for movement of the cage is provided. The unit for detection of the movement of the cage enables a conclusion about the movement of the cage to be made by way of the detection of the movement of a movable part of the drive unit.
Moreover, a speed-limiting unit can be provided, wherein the unit for detection of the movement of the cage enables a conclusion about the movement of the cage to be made by way of the detection of the movement of a movable part of the speed-limiting unit.
The unit for detection of the movement of the cage can advantageously comprise a flexible shaft which is connected with the movable part of the drive unit. The display unit comprises a rotating disc or a tachometer.
The unit for detection of the movement of the cage comprises, in a further embodiment of the invention, a flexible shaft which is connected with the movable part of the speed-limiting unit. The display unit comprises a rotating disc or a tachometer.
In one embodiment of the invention the speed-limiting unit comprises a cable, wherein the means for reproducing the position of the cage comprises marks at the cable of the speed-limiting unit.
Moreover, a support means, which is connected with the cage, can be provided, wherein the means for producing the position of the cage comprises marks at the support means.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.